Anisotropies and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory

The Pierre Auger Collaboration

Research output: Contribution to conferencePaper

Abstract

The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E > Eth = 5.5×1019 eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E > Eth are heavy nuclei with charge Z, the proton component of the sources should lead to excesses in the same regions at energies E/Z. We here report the lack of anisotropies in these directions at energies above Eth/Z (for illustrative values of Z = 6, 13, 26). If the anisotropies above Eth are due to nuclei with charge Z, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies.

Original languageEnglish (US)
Pages137-140
Number of pages4
DOIs
StatePublished - 2011
Event32nd International Cosmic Ray Conference, ICRC 2011 - Beijing, China
Duration: Aug 11 2011Aug 18 2011

Other

Other32nd International Cosmic Ray Conference, ICRC 2011
CountryChina
CityBeijing
Period8/11/118/18/11

Keywords

  • Anisotropies
  • Chemical composition
  • Pierre auger observatory
  • Ultra-high energy cosmic rays

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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    The Pierre Auger Collaboration (2011). Anisotropies and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory. 137-140. Paper presented at 32nd International Cosmic Ray Conference, ICRC 2011, Beijing, China. https://doi.org/10.7529/ICRC2011/V02/0868